Valve-truing tool



CII

Patented Mar. 23, Y1926.

rin-fl'ruaT sam/iras .EDWARD I/AARLE, 02Ev OAKLAND, CALFORNIA.

VALVE-TRUING TOOL.

Application filed August 27, 1919.' Sera1 Noi 329,235.

for truing or dressing thefaces of" valvesk especially theV poppetvalves of' internal combustion engines.

An object of theinvention is to provide a truing tool which will insureaccurate re-l sults' notwithstanding the characteristic deformation ofthe valve stem due to wear.

Another object ofthe invention is to provide a device such as willenable the valve to be quickly and Securely placed in posi-k tionfor thetruing operation.

The `invention possesses other objects and features ofadvantage, some ofwhich, with the foregoing, will-be set forth in the followingdescription of the preferredv form of my invention which iSillnStratedinthe drawings accompanyingand'forminga part of the specification; It isto be understood that l do not limit myself to the showing made by thesaid drawings and description, as I may adopt variations of thepreferred form within the scope of my invention as set forth in theclaim. l

Referring to said drawings:

Fig. 1 is a plan view of the truing tool, the valve being shownpositioned therein.

Fig. 2 is a vertical section of the device, the plane of the sectionbeing indicated by the line 2-2 of Fig. 3.

Fig. 3 is a vertical section taken on the line 3 3 of Fig. 2.

Frequently the poppet valves of an internal combustion engine becomewarped or misshapened so that they do not seat properly. The valve facemust then be trinnned until the original circumference and taper obtainonce more. During this trimmingV operation the valve is usuallysupported by mounting the valve stem for rotation in a pair of alignedclamps. It is imperative that these clamps should so hold the stem thatthe valve will rotate in aliixed cooperative relation with the cuttingblade of the truing tool and thereby become accurately trimmed. Sincethe clamps are generally two in number they will therefore engage thestem at two spaced points intermediate its ends. If the valve stem isofthe saine diameter thruout its length then the clamps will hold thevalve properly. However the stem invariably liecomesinuchl thinner atthat portion which is continu# ally pressing against the sides of itsbear ing when the engine is operating, due to the pressure ofthe intakeor exhaust' gases. Since lthe length of the stems for the diii'erentengines vary considerably, it is almost G5 invariably the case thatunless labor entailing 4adjustments aremade, one ofi the tool clampswill engage a thin section of the stein and the'othera thick section,thereby throwing the valve completely out of alignment and making itimpossible to trim the valveY with any degree of accuracy.

In accordance with my invention the valve stem automatically assumes acorrect position and therefore insures an accurate cutting of the valve.

detailed description of my invention follows:

The apparatus comprises a pairrof jaws 2 andB between which thestem el.of the valve 5 is arranged to bel positioned.' The jaws are pivotedtogether at one edge, the eyes 6 and 7 and pin 8 disposed on the innerside of the jaws being partly provided for that purpose. The jaw 2 ispreferably` 85 formed with an integral supporting member 9 which may beset in a vise to anchor the tool if desirable.

Means are provided as hereinbefore mentioned, for insuring the correctpositioning 90 of the valve stem.4 Formed on the inner sides of the jawsand preferably integral with the eyes 6 and 7 are a plurality of' spacedlongitudinally aligned teeth l0 and 12. T he teeth l0 of the jaw 2 arearranged to lit in the spaces 13 between the teeth l2 of the jaw 3 andvice versa the teeth l2 are arranged to engage the spaces 14 of the jaw2. By referring to Figure 2 it will be clearly seen that when a valvestem having a worn portion such as at l5, is inserted between the jaws,at least one tooth of each jaw will engage the undeformed portion of thestem at both the forward and rear end of the jaws, thereby insuring theproper l truing of the valve. .j

The teeth: are each provided with a V-shaped recess 16 thereby providinga four point contact between each pair of teeth that are in Contact withthe stem. This construction has several advantages over a three pointcontact, since a better bearing is provided within which the stein mayrotate and a mnch smaller error in alignment ot the valve will prevailin case an insultieient number of teeth engage the valve stem.

Simple means are Vprovied for normally maintaining the jaws in anextended position and :tor drawing said jaws together when it is desiredto grip the valve. Enoireling the pin 8 and interposed between the awsis a spring 17 which presses against the inner sides of the jaws andtherehvY tends to keep the jaws extended. Engaging the free edges oitthe jaws 2 and 3 is a screw threaded bolt 1S formed. with a reotangularneck 19 which loosely engages a correspondingljV shaped aperture 19provided in the jaw 2. rlhe threaded end of the holt extends thru anenlarged aperture 20 formed in the jaw 3. A winged nut 2l engages theholt on the outer .side of the jaw 3 while the head 22 of the holt`hearsagainst the outer side ot the jaw 2. lilith this con struction the jawsmajv he opened or Closed hy simplyv turning a single nut, thereliijTsaving considerable time dispensing with a nnmher of loose parts.

rlfhe jaw 2 is provided at one end with a Cutting hlade 23 which has itscutting edge E34 disposed in. the path of the valve tace The oppositeend of the jaw 2 is provided with an adjustable screw 2G which isarranged to engage the free end of the valve stem to limit the amountthat the valve majT be trimmed.

In operation ot the device the valve stem mvp/,vas

is inserted in the recesses i6 and the winged nut 2l rotated until thestein is properly gripped. The screw 26 is then adjusted so that theface of the valve properly contacts with the cutting blade. To rotatethe valve it is convenient to use an ordinary brace (not shown) providedwith a key 27 that can he inserted in the recesses 28 provided in thevalve.

l claim:

A valve truing tool, Comprising a pair ot jaws pivotally connectedadjacent one edge and arranged to he longitudinally disposed along` thevalve'stein, a plurality of longitudinally spaced teeth on the innerside oi each jaw arranged to cooperatively engage onljT full-sizedportions of said stern throughout its length, the teeth of each aw beingarranged to engage in the spaces between the teeth ot' the other jaw, acutting member adjustablv Secured to one end of one of said jaws andhaving its cutting portion positioned to lie in the path of the valveface when the valve is operatively held in the tool, means resilientlyurging said jaws apart a single means for holding said jaws together toretain the teeth in engagement with said stein and means provided on thejaw carrying said cutting member for limiting the movement of the valveagainst said Cutting member.

ln testimony whereof, I have hereunto set my hand at Oakland,California, this 16th day of August 1919.

EDWARD LAPARLE.

